324 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. lxiv. 



could scarcely be employed with any hope of success. 

 The three lower temperatures, viz. 25' C, 30° C, and 

 35°C., had however no harmful effect, as, after exposure to 

 them for the above-mentioned period, all the buds germin- 

 ated normally in light at the ordinary temperature, without 

 any appreciable retardation, giving a series of results quite 

 comparable with those obtained by Forest Heald in the 

 case of moss spores, which, however, were killed at a 

 slightly lower temperature, viz. 35° C. 



With the same object in view, buds were kept in dark- 

 ness, at the ordinary temperature of the room (between 

 10 C. and 15''C.), -in normal inorganic solution containing 

 low percentages of the following organic food materials, 

 each being used at strengths of 1, 2, 5, and 10 per cent, 

 respectively : — 



Nitrogenous substances — Peptone. Carbamide, Asparagiue, Glyco- 



coll. 

 Carbohydrates, Aldohexoses. — d. -Glucose, d.-Mannose, d. -Galactose. 

 Ketohexose. — d.- Fructose. 

 Disaccharoses. — Cane Sugar, Maltose, Lactose. 



Care was taken to sterilise all the liuids by repeated 

 steaming, while the buds before being placed in the tubes 

 were rapidly washed in a one-tenth per cent, solution of 

 mercuric chloride and at once rinsed several times in 

 sterilised water. iSTo indication of germination was, how- 

 ever, observable in any of the tubes at the end of the three 

 summer months of June, July, and August during which 

 the experiment was continued. In all cases, buds formed 

 in the previous year were employed, and at the close of the 

 experiment were kept in fresh water till the following 

 spring, when they all without exception germinated as 

 freely as normal buds of the preceding autumn. 



As the buds contain in general a considerable amount of 

 chlorophyll, it seemed possible that a photosynthetic 

 absorption of carbon dioxide might be essential to germin- 

 ation, though this possibility was to a considerable extent 

 discounted by the appearance, as above mentioned, of 

 similar phenomena in seeds which contain no chlorophyll, 

 and by the want of agreement between the spectral position 

 of the rays which promote germination and tliose which 

 initiate photosynthesis, as well as by Forest Heald's results 

 with moss spores. 



